docs: def process_dynamodb_differ_record(record, current_model, durable_model, diff_func=None):
      """
      Processes a DynamoDB NewImage record (for Differ events).
  
      This will ONLY process the record if the record exists in one of the regions defined by the PROXY_REGIONS of
      the current Proxy function.
      """
      diff_func = diff_func or default_diff
  
      # Nothing special needs to be done for deletions as far as items that are too big for SNS are concerned.
      # This is because the deletion will remove the `configuration` field and save the item without it.
      if record['eventName'] == 'REMOVE':
          # We are *ONLY* tracking the deletions from the DynamoDB TTL service.
          # Why? Because when we process deletion records, we are first saving a new "empty" revision to the "Current"
          # table. The "empty" revision will then trigger this Lambda as a "MODIFY" event. Then, right after it saves
          # the "empty" revision, it will then delete the item from the "Current" table. At that point,
          # we have already saved the "deletion revision" to the "Durable" table. Thus, no need to process
          # the deletion events -- except for TTL expirations (which should never happen -- but if they do, you need
          # to investigate why...)
          if record.get('userIdentity'):
              if record['userIdentity']['type'] == 'Service':
                  if record['userIdentity']['principalId'] == 'dynamodb.amazonaws.com':
                      LOG.error(f"[TTL] We received a TTL delete. Old Image: {record['dynamodb']['OldImage']}")
                      old_image = remove_current_specific_fields(record['dynamodb']['OldImage'])
                      delete_differ_record(old_image, durable_model)
  
      if record['eventName'] in ['INSERT', 'MODIFY']:
          arn = record['dynamodb']['Keys']['arn']['S']
          current_revision = deserialize_current_record_to_durable_model(record, current_model, durable_model)
  
          if not current_revision:
              LOG.error(f'[?] Received item too big for SNS, and was not able to find the original item with ARN: {arn}')
              return
  
          if record['eventName'] == 'INSERT':
              current_revision.save()
              LOG.debug('[+] Saving new revision to durable table.')
  
          elif record['eventName'] == 'MODIFY':
              modify_record(durable_model, current_revision, arn, current_revision.eventTime, diff_func)